Jade, Nephrite, and Jadeite
Jade is a secondary birthstone for the month of March. For people born in March, jade is the mystical birthstone, which is based on the Tibetan birthstone chart dating back thousands of years. A mystical birthstone represents the spiritual world, which is why some people prefer these types of birthstones to modern ones.
There are two different minerals that are commonly called "jade": jadeite and nephrite. In 1863, French mineralogist Alexis Damour discovered that what at the time was being called jade, were in fact 2 distinct mineral species, namely jadeite, and nephrite.
Many different rocks and minerals have been marketed as jade, especially nephrite and serpentine, but also green quartz, vesuvianite (californite), etc. Gemmologists, however, usually restrict the name to just jadeite and nephrite, both characteristically forming very tough, fine-grained rocks. Nephrite is much more common than jadeite, and is a tremolite and/or actinolite-rich rock, and this is why it has been classified here as a type of metamorphic rock rather than a generic term.
Jadeite is a mineral in its own right, a pyroxene; nephrite, an amphibole, is a variety of tremolite or actinolite. Jadeite is made of interlocking, blocky, granular crystals, whereas nephrite crystals are fibrous. These two different textures can sometimes help distinguish between them: nephrite often appears fibrous and silky; jadeite commonly has a more sugary or granular texture. Crystals of jadeite do occur, but they are rare. They are usually found in hollows within massive material and are short prismatic in habit. Jadeite appears in a number of colors (pure jadeite is white with other colors including green (colored by iron), lilac (colored by manganese and iron), and pink, brown, red, blue, black, orange, and yellow (colored by the inclusions of other minerals) Emerald-green jadeite (colored by chromium) is called imperial jade), whereas nephrite has a much more limited color range. Jadeite usually occurs in metamorphic rocks with higher-pressure origin than nephrite, although some has been found in lower pressure metamorphic rocks. It is widespread in metamorphic rocks formed at subduction zones.
Wheatherd jadeite usually develops a brown skin, which is often incorporated into carvings. It frequently has a dimpled "orange-peel" surface when polished.
Nephrite jade has its cultural roots in the smoke-dimmed caves and huts that sheltered prehistoric humans. In China, Europe, and elsewhere around the world, Stone Age workers shaped this toughest of minerals into weapons, tools, ornaments, and ritual objects. Their carvings invoked the powers of heaven and earth and mystic forces of life and death. Stemming as far back as approximately 5000 BCE, jade was known to be used in Chinese ritual ceremonies. The Chinese associate jade with clarity of mind and purity of spirit.
While jade dated back to before 1700 BCE was discovered near the Yangtze River, it was around then, during the Xia Dynasty, that Chinese culture saw a major uptick in crafts made from the stone. During those days, most of the jade objects created were relics for the Emperor. But it was during Yin Dynasty (C. 1550 BCE) that jade began to be used for other purposes—most relevantly to us, to create jewelry.Most people imagine green when they think of jade, but it wasn’t until relatively recently, during the Qing Dynasty (1644-1911 CE) that it surpassed white in general popularity. Until then, China hadn’t much ventured into mining the stone in other territories, and a bright green color was hard to be found. But during the 18th and 19th centuries, the Chinese began mining it in neighboring Myanmar (also known as Burma), and green was readily abundant there. Once jade became widely available, it quickly dominated as the preferred color, which holds true to this day.
The ancient relationship between this gemstone and humanity persisted into modern times among native societies in New Zealand and parts of North America. In China it evolved into an artistic tradition that has flourished for more than 3,000 years.
In Central America, the Mayans and the Aztecs prized jadeite jade. They used it for medicinal purposes as well as for jewelry, ornaments, and religious artifacts. The name jade comes from the Spanish expression piedra de ijada—literally “stone of the pain in the side.” Early Spanish explorers named it after they saw natives holding pieces of the stone to their sides to cure or relieve various aches and pains. Jadeite also symbolizes prosperity, success, and good luck.
It was in China—where the gem-carving tradition was already thousands of years old—that jade reached its peak as an important artistic medium. The first jadeite reached China from Burma (now known as Myanmar) in the late 1700s, and late eighteenth and early nineteenth century carvers created masterpieces that are still unsurpassed in concept, design, and technical execution.
Myanmar is a major source of jadeite and in particular imperial jade. Other sources are in Japan and California. Ancient tools and weapons of jadeite are found in Myanmar, in the same way that nephrite objects have been discovered in China. A very small amount of jadeite found its way into China over the centuries, and from the 18th century, it was imported in large quantities from Myanmar and soon displaced nephrite as a favored carving material. Because of its value, other green gemstones are often misnamed "jade". Jade from Myanmar has been divided into five groups according to the main mineral constituent of the respective sample (Franz et al., 2014): (1) jadeitites with kosmochlor and clinoamphibole, (2) jadeitites with clinoamphibole, (3) albite-bearing jadeitites, (4) almost pure jadeitites and (5) omphacitites.